The essentials of heat pump operation consist in converting thermal energy collected from the natural environment (lower temperature reservoir) into useful energy used for domestic hot water heating and production (higher-temperature heat reservoir).
An evaporator and a condenser transfer the energy generated in intermediate circuits and are the main elements of the circuit, apart from the compressor and expansion valve. The operation of a compressor heat pump is based on using the natural energy resources provided by the ground, atmospheric air and surface or underground waters.
Heat pumps are ever more often used in modern, energy-efficient construction. They are automated, maintenance-free and economical. An appropriately installed heat pump, may ensure significantly lower house heating bills and return on the investment will be quick.
Air heat pumps can be used both for heating and cooling a building. They are an excellent alternative to the ground source heat pumps. They are ideal in situations where there is not enough space to install a ground exchanger on the plot.
Two types of air heat pumps are distinguished. An air-to-air pump is used the most frequently. It recovers heat from the air and then transfers it inside the building or outside the house, depending on the season.
The other type of air pump is the air-to-water pump, which provides a high efficiency ratio even at air temperatures below zero. Air-to-water pumps may be used for house heating and domestic hot water production. These pumps also allow for cooling the building using a reversible circuit.
Absorption pumps are installed in places where excess waste or process heat is available. Absorption heat pumps differ from the compressor heat pumps in that their operation is forced differently. It requires a supply of heat, not electricity. Electricity is needed only for supplying the pumps. Absorption heat pumps consist of a condenser, evaporator and expansion valve. The role of a mechanical compressor used in a compressor heat pump is fulfilled by a set of devices, such as a desorber, absorber and pump, called a thermal compressor.
Ammonia-to-water and lithium bromide-to-water type absorption heat pumps are available on the market. In the case of the lithium bromide devices, water is the cooling medium and lithium bromide is the absorbent. In the case of ammonia devices, ammonia is the medium and water is the absorbent.
Ground source heat pumps are the most economical type of heat pumps. Using collectors, these tap into the energy resources of the ground, deep water wells and waters from lakes or streams. Achieving fixed device parameters is possible thanks to stable ground temperature. This forms the basis for the system’s economical operation, thus ensuring a stable (heating) temperature in the apartment.
There are two variants of ground collectors: horizontal and vertical. The surface exchanger uses the energy of the sun and rainwater, therefore appropriate plot development plays a key role here.
The heat pump can also fulfill a cooling function by using a reversed cycle. Reversible heat pumps are more expensive than the traditional ones. They allow not only to supply the central heating system and heat domestic hot water, but also to cool rooms in the summer. Depending on the season, the brazed plate heat exchanger installed in the pump operates as a condenser or an evaporator.
Dedicated heat pumps are used in countries with a colder climate, where air conditioning is not needed, which makes using reversible heat pumps unprofitable. Due to the fact that a special heat pump will be used only for heating, operation costs will be much lower than in the case of reversible heat pumps.
Industrial heat pumps may provide heating and cooling, using energy from different processes. Installing a high-power heat pump in industrial buildings may generate large benefits in terms of cost reduction, pollution emissions and air quality improvement.
Pump operation consists in collecting water from an industrial process in a tank. In the summer, the water stored is cooled by a circuit with fans. In the winter, the tanks constitute the lower-temperature heat reservoir in the pump. Water from the tank is routed to the heat pump evaporator, where it transfers its heat to the cooling medium. CH water is heated in the pump condenser and the heat generated is supplied to the central heating system.
